Basic Statistic in Technology and Assessment Mary L. Putman

Levels of Measurement Ordinal Level Interval Level Nominal Level Ratio Level

Levels of Measurement (cont.) Nominal Level Simplest and least precise Differentiates attribute or property Little statistical value Examples: Locker Number #20 Social Security Number

Levels of Measurement (cont.) Ordinal Level Has the property of order (rank) Indicates difference (more or less) Indicates direction of difference Not mathematically meaning Examples: Team rankings Class rankings

Levels of Measurement (cont.) Interval Level More precise measure; calculations meaningful Provides equal difference in characteristic being assessed Zero point is arbitrary Example: Temperature Cognitive Measures (i.e. -- I.Q. Test)

Levels of Measurement (cont.) Ratio Level Most precise and useful level Absolute zero Ratio number can make statements such as … Twice as big/.. Twice as fast Examples: Distance throw Speed run

1. Numbers on a football jersey. 2. Timed scores for 100 meter dash. 3. Mr. RU, first place runner up. 4. Gender classification for M/F. 5. Speedometer reading of 60 mph. 6. Temperature of 32 degrees 7. Wrestler’s height and weight.

Measures of Central Tendency Mode Score that occurs most often Median The point at which half the scores fall above and below Mean The numerical average.. The sum of the scores divided by N (the number of scores)

Measures of Variability Range The difference between the highest score and lowest score Standard Deviation The most common measure of variability Spread of scores Amount each score deviates from the mean

Measure of Relationship Correlation You must have two sets of scores for each individual in order to use the correlation Identifies the direction and strength of the relationship between two sets of scores. The scores will range from to –1.00

Measure of Relationship (cont.) Strength (correlation coefficient) Number will range from 1.00 to.00 The closer to one the number is the stronger the relationship Ranges:.80 to 1.00 = high correlation.60 to.79 = moderately high correlation.49 to.59 = moderate correlation.20 to.39 = low correlation.00 to.19 = no relationship

Measure of Relationship (cont.) Direction The direction is identified by a + or – sign +.. Both sets of scores have the higher score as the better score or lower score the better score. -.. One set of scores the higher score is better, the other set of scores the lower score

Measure of Relationship (cont.) Examples of Direction of Relationship  Twelve minute walk run to Shuttle Run  Golf Score to Upper Body Strength  Over GPA to Grade in Technology/Assess  GPA to SAT  Stress Test (high =more stress) to Obesity (BMI = higher means fatter)

Terminology Subjects People participating in your research project Variables What you are measuring… speed, body composition, stress Test/Assessment The instrument you are using to collect the data in your research area.

Terminology (cont.) Measurement The process/procedures used to collect the data (scores) Evaluation What you do with the information, what conclusion you reeach once the data is analyzed, what action do you take?